Key Lifestyle Behaviors Cut Risk of Sudden Cardiac Death Among Women

Summary
More than 50 percent of the deaths due to heart disease are found to be “sudden cardiac deaths,” or SCDs, that result in death within an hour of the onset of symptoms. In women, SCD may often be the first manifestation of an underlying heart disease. A large population-based study attempted to see if a healthy lifestyle could reduce the risk of SCD in women. The results of this study showed that women who did not smoke, had normal body weight, exercised often, and consumed more fruit, greens, grains, nuts and fish, had a lower risk of SCD.

Introduction
“Sudden cardiac deaths” kill nearly 310,000 Americans each year. Death occurs within an hour of the onset of symptoms like chest pain, breathlessness and profuse sweating. On an examination after death, extensive heart disease is often detected. It is seen that women who have had no previous symptoms of cardiovascular disease succumb to SCD. Heart disease can be prevented by certain modifications in lifestyle, like losing weight, quitting smoking, maintaining a healthy diet and abstaining from alcohol. These modifications can reduce the risk of SCD, as well. However, the combined effect of all these factors on the risk of death due to SCD has not yet been investigated. This study attempted to evaluate the lifestyle factors and their possible effect on the risk of death due to SCD in women.

Methodology
* The study involved 81,722 women, who were already a part of a large ongoing survey called the “Nurses’ Health Study.” The study spanned between 1984 and 2010.
* All the participants answered questionnaires, every two to four years, regarding their lifestyle and dietary habits during the study.
* The incidence of SCD in the participants was determined. For the purpose of this study, SCD was defined as death within an hour of the onset of heart attack-related symptoms.
* A lifestyle that entailed a low risk had four key componenets: 1) a non-smoking status, 2) having normal body weight, 3) exercising more than a half hour per day and 4) maintaining a healthy diet. A healthy diet included fruits, vegetables, nuts, legumes, whole grains, fish and moderate alcohol consumption.

Key findings
* During the 26 years of this study, 321 cases of SCD were recorded. The women who succumbed to SCD were 72 years of age, on average.
* Low risk factors in lifestyle significantly reduced the risk of SCD in the population. The risk of SCD was 22 per 100,000 people in women who had none of the low risk habits.
* The data suggest that 81 percent of SCD may have been avoided had all women been in the
low-risk group for all four lifestyle factors.

Next steps/Shortcomings
The authors agree that an assessment of all the factors that affect lifestyle and related heart disease for such a large population, over such a long period, is fraught with errors. In addition, many participants failed to appear for follow-up studies. They also add that racial and ethnic differences, and essentially genetic predispositions, may affect the risk of SCD. These need further evaluation and study.

Conclusion
Prevention of sudden cardiac death is one of the few approaches to reduce mortality rates due to this silent killer. SCD is difficult to prevent because it often strikes without warning and often manifests in people who were never expected to be at risk of acquiring heart disease. Women are especially vulnerable to SCD. The present study examined a large number of nurses, over a period of 26 years, to assess the combined effects of lifestyle factors – like smoking habits, body weight, physical exercise and diet – on the risk of SCD. The results predictably showed that a healthier lifestyle is linked to a lesser risk of SCD and should be adopted as a public health measure to help prevent its occurrence.